The Census controversy is the latest example of the White House’s being happy to avoid assessing its law.

When the New York Times reported yesterday that the U.S. Census Bureau is making significant changes to the part of its Current Population Survey that calculates how many Americans have health insurance — thus making it difficult to measure the effects of Obamacare — the initial media reaction on Twitter was outrage.

“Getting worked up into an increasingly heated health nerd rage about the Census changes,” wrote Vox’s Sarah Kliff. “I’m speechless. Completely inexcusable. The administration deserves all of the criticism it will get, and then some,” fumed Megan McArdle. Josh Barro called the Census Bureau’s change “insane” and asked, “Why can’t this wait?”

Why indeed? Such a change comes at seemingly the worst possible time vis-à-vis the health-care law. How are we to judge whether Obamacare has reduced the number of uninsured if we introduce a completely new way to calculate the uninsured rate? Census officials told the Times “that it will be difficult to measure the effects of President Obama’s health care law in the next report, due this fall” using their new report. Changing the survey means “it is likely that the Census Bureau will decide that there is a break in series for the health-insurance estimates,” they say — meaning they won’t be able to compare data from previous years with the data collected under the new method.

It turns out, however, that the outrage on Twitter was a bit premature. As Patrick Brennan promptly noted, the White House later clarified to Sarah Kliff that the new survey questions — which ask for details about when people had coverage in the past year, and from what source, and are therefore more precise than the old survey method — would be used to collect data for 2013. That will make possible an apples-to-apples comparison of the uninsured from 2013 to 2014, when Obamacare’s exchanges and Medicaid expansions took effect. Kliff correctly notes, however, that the change “will make it difficult to compare the uninsured rate for 2012, the last year for the old questions, and 2013, the first year for the new questions.” It also means that the CPS will essentially have only one year of pre-Obamacare data, as opposed to decades’ worth, which is presumably why Census officials called the timing “unfortunate.”

So although the change is not as bad as it initially appeared to be, it still mangles one huge source of data on Obamacare and the uninsured, making it more difficult to assess the law’s effects on health-insurance rates. (Other large surveys, collected by the government and the private sector, do exist.) Because these surveys lag by a year, we’ll get 2013 numbers in the fall of 2014, and won’t be able to compare them with this year’s numbers until the fall of 2015, by which time whatever outrage is left will likely be much diminished.

But Census officials also said the unfortunate timing was “coincidental.” Arguably, measuring the net increase in health-insurance coverage is the only meaningful metric for Obamacare. Changing the way Census calculates this metric now, when we’re in the middle of implementing massive changes to health-insurance markets, seems like a good way to skew the numbers in the administration’s favor — especially if the new survey methodology is likely to yield a lower uninsured rate. The Times reports that the Obama administration was consulted on the new questionnaire and that it approved the changes — if the White House wanted the Census to produce data that could be used to assess Obamacare, presumably it could have asked that the Census Bureau hold off on the changes.

The problem here underscores an emerging pattern of passive obfuscation on the part of the administration when it comes to gathering useful data about Obamacare. Calculating how many people are gaining or losing health insurance isn’t an easy or straightforward task to begin with, but the administration should have produced better data by now than it has. After all, if there’s one thing Americans want to know about the ACA come this fall, it’s whether the law is reducing the number of uninsured like the administration said it would.

So far, the numbers from both private and government sources vary. A much-cited Gallup poll last month indicated that the uninsured rate is dropping after hitting an all-time high of 18 percent in the third quarter of 2013. The two demographic groups that saw the largest drop in the uninsured were black Americans and those earning less than $36,000 a year — by 2.6 and 2.8 percentage points, respectively. That makes sense, given that the subsidized Obamacare exchange plans are most attractive to uninsured people with low incomes. Yet a pair of recent surveys from RAND Corporation and McKinsey indicate only about a third of those who enrolled on the exchanges were previously uninsured, undermining hopes that the law would reduce their ranks significantly.

But as Megan McArdle noted at the end of March, it wouldn’t be impossible, or even all that difficult, for the government to figure out how many uninsured people are gaining coverage through the Obamacare exchanges. She quotes health-industry expert Bob Laszewski, who explains how the administration could easily get the data:

We only need ask the carriers for two numbers:

1. The number of people they insured (and were paid for) in both the individual and small group markets as of December 31, 2013 — the day before Obamacare started covering people.

2. The number of people that were insured (and paid for) in both the individual and small group markets on a specific date — March 31, 2014, for example.

Why hasn’t the administration done this? It would have been easy — just as it would have been easy for officials at the Department of Health and Human Services to require insurers on the exchanges to report how many of the 7.5 million exchange enrollees have paid their first month’s premium so we have a clear picture of how many of them are actually covered.

Come to think of it, there are many things the Obama administration could have done in recent months to give us a more accurate picture of how the ACA is working. For example, the CBO estimates that because of Obamacare, 7 million Americans will gain coverage through Medicaid or the Children’s Health Insurance Program (CHIP) in 2014. Yet enrollment for those programs fluctuates throughout the year, and millions of people would have signed up — and others kicked off — with or without Obamacare. As Sean Trende explained back in January when the White House was claiming 4 million people had gained coverage through Medicaid expansion, “It’s a virtual certainty that the number of enrollments attributable to Obamacare is an order of magnitude less than the 4 million sign-ups implied, and the number of people [on Medicaid] who would actually lose their insurance if Obamacare were repealed is probably around 200,000 to 300,000.” All Trende did to arrive at this conclusion was closely read some documents from the Centers for Medicare and Medicaid Services (CMS), which tracks monthly enrollment. A week later, he did it again. Anyone at the White House or HHS could have done the same, but no one did.

Which brings us to this latest question: Why did the administration approve the Census Bureau’s change to the CPS instead of delaying it for a year or two to ensure a continuity of data, pre- and post-ACA? Why make it harder to assess the effects of the law?

Perhaps it’s the result of gross incompetence — we’ve certainly seen that aplenty from the Obama administration. But a skeptic might conclude that instead it is part of a sustained effort to thicken the fog surrounding Obamacare, and instead of letting Americans come to their own conclusions based on the best available evidence, obscure the law’s effects in order to persuade us that it is working as planned, its critics have been discredited, and the debate is finally over.

— John Daniel Davidson is a senior policy analyst for the Center for Health Care Policy at the Texas Public Policy Foundation.